BPB of unpartitioned boot volume

Offset	Data			Comment
--------------------------------------------------------------------------------------------------------------------------
0x000	0xC3, 0x5A, 0x50	Jump to bootloader code (assume sector loaded to 0x5000)
0x003	'ZEPHYROS'		OEM Name
0x00B	0x0200			512 bytes per sector
0x00D	0x01			1 sector/cluster
0x00E	0x0006			Reserved Sectors
0x010	0x02			Number of FATs
0x011	0x0000			Reserved
0x013	0x0000			16-bit sector count, default to 0 if 2^16 or over.
0x015	0xF8			Media descriptor
0x016	0x0000			Reserved
0x018	0x0000			Sector/Track, unused in ZFAT
0x01A	0x0000			Number of heads, unused in ZFAT
0x01C	0x00000000		Hidden sectors before current partition
0x020	0x09502F90		Sector count, default to 0 if below 2^16. (80GB volume)
0x024	0x00125704		Sectors per FAT
0x028	0x0000			Active FAT flags.
0x02A	0x3031			Version number '0.1'
0x02C	0x00000002		Root directory initial cluster.
0x030	0x0001			FSINFO sector number
0x032	0x0006			Backup BPB
0x034	0x000000000000		Reserved
0x040	0x00			Drive Number
0x041	0x00			Reserved
0x042	0x29			Extended boot signature
0x043	0x00000000		Volume serial number
0x047	'ZEPHYRBOOT '		Volume Label
0x052	'ZFAT    '		File system identifier, space padded
0x05A	boot code		Boot code
0x1FE	0xAA55			Boot signature


FSINFO sector

Offset	Data			Comment
--------------------------------------------------------------------------------------------------------------------------
0x000	0x41615252		FSINFO start signature
0x004	0			Reserved, 480 bytes.
0x1E4	0x61417272		FSINFO mid signature
0x1E8	0xFFFFFFFF		Unknown count of free sectors
0x1EC	0xFFFFFFFF		Unknown first free cluster
0x1F0	0			Reserved, 12 bytes
0x1FC	0xAA550000		FSINFO trail signature



Root Directory

Offset	Data			Comment
--------------------------------------------------------------------------------------------------------------------------
0x00	'ZEPHYRBOOT '		Volume Label, includes extension
0x0B	0x08			Volume Label flag set
0x0C	0x00			Reserved, set to 0.
0x0D	0x??			Creation time, tens of milliseconds
0x0E	0x0000			Creation time
0x10	0x0000			Creation date
0x12	0x0000			Last access date
0x14	0x0000			High byte of first cluster location
0x16	0x0000			Last modified time
0x18	0x0000			Last modified date
0x1A	0x0002			Low byte of first cluster location
0x1C	0x0000			File size in bytes


Determining amount of nibbles(4-bit groups) needed for each cluster of a FAT filesystem:
clusSiz*(2*secSiz)+nfats*fatNibls

Assume a cluster size of 1, sector size of 512, number of fats as 2, and nibbles per fat of 8
1*(2*512)+2*8 = 1040 nibbles, or 520 bytes.

remSects will be assumed to be 156,249,992 for an 80GB(80,000,000,000B) volume with 8 sectors reserved.

numClus <= (2*remSect*SecSiz-2*nfats*fatNibls)/(2*clusSiz*secSiz+nfats*fatNibls) = 153,846,145.93846153846153846153846
or
numClus <= ((remSect+2*clusSiz)*2*secSiz)/(2*clusSiz*secSiz+nfats*fatNibls)-2 = 153,846,145.93846153846153846153846

fatLen will be the size of the FAT in sectors, rounded up

fatLen <= ((numClus+2)*fatNibls)/(secSiz*2) = ceil(1,201,923.0234375) = 1,201,924 sectors